Tc-99m produced by proton irradiation of a fluid target system

Abstract

Methods for producing Tc-99m radioisotope by proton irradiation of a fluid target matrix. A method of producing Tc-99m includes irradiating a fluid target matrix comprising Mo-100 with a proton beam to transform at least a portion of Mo-100 to Tc-99m. Optionally, the fluid target matrix further includes at least one of O-18, O-16, or N-14, which upon exposure to the proton beam concurrently transform at least a portion of O-18 to F-18, at least a portion of O-16 to N-13, at least a portion of the O-16 to O-15, or at least a portion of N-14 to C-11. The method further includes isolating Tc-99m and optionally at least one of F-18, N-13, O-15, or C-11 from the irradiated fluid target matrix. An additional source of Tc-99m is available from the decay of Mo-99 that is co-produced from the Mo-100 during irradiation with the proton beam.

What is claimed is: 
     
       1. A method of producing Tc-99m, the method comprising:
 irradiating a fluid target matrix comprising Mo-100 with a proton beam to directly transform at least a portion of Mo-100 to Tc-99m via a Mo-100(p,2n)Tc-99m reaction and provide an irradiated fluid target matrix; and 
 isolating Tc-99m from the irradiated fluid target matrix. 
 
     
     
       2. The method of  claim 1 , wherein the fluid target matrix further comprises water. 
     
     
       3. The method of  claim 2 , wherein the Mo-100 is derived from a water soluble molybdenum compound selected from the group consisting of molybdenum oxide, ammonium molybdate, and alkali metal molybdates. 
     
     
       4. The method of  claim 2 , wherein the water is H 2   18 O, and at least a portion of the O-18 is transformed to F-18. 
     
     
       5. The method of  claim 4 , further comprising:
 separating at least a portion of the F-18 from the irradiated fluid target matrix. 
 
     
     
       6. The method of  claim 2  wherein the fluid target matrix has a pH of about 2 to about 12. 
     
     
       7. The method of  claim 1  further comprising:
 isolating the Mo-100 from the irradiated fluid target matrix to provide a recovered sample of the Mo-100; and 
 irradiating the recovered sample of the Mo-100 with a proton beam to transform at least a portion of the recovered sample of the Mo-100 to the Tc-99m. 
 
     
     
       8. The method of  claim 1 , wherein the fluid target matrix comprises an organic liquid. 
     
     
       9. The method of  claim 1 , wherein the fluid target matrix comprises a gas or a mixture of gases, and the Mo-100 is derived from a gaseous molybdenum compound. 
     
     
       10. The method of  claim 1  wherein protons of the proton beam have an average energy of at least about 7 MeV. 
     
     
       11. The method of  claim 1 , wherein isolating Tc-99m from the fluid target matrix comprises:
 transferring the irradiated liquid target matrix out of an irradiation target body; and 
 separating at least a portion of Tc-99m from Mo-100. 
 
     
     
       12. The method of  claim 11 , wherein separating at least a portion of Tc-99m from Mo-100 comprises:
 loading a sample of the irradiated liquid target matrix onto a solid phase extraction system; 
 eluting the Tc-99m and the Mo-100 from the solid phase extraction system with at least one eluent solution to separate at least a portion of the Tc-99m from at least a portion of the Mo-100; and 
 collecting at least a portion of the at least one eluent solution discharged from the solid phase extraction system to provide an eluted technetium fraction enriched in the Tc-99m and an eluted molybdenum fraction enriched in the Mo-100. 
 
     
     
       13. The method of  claim 12 , wherein the eluted technetium fraction is eluted from the solid phase extraction system before the eluted molybdenum fraction. 
     
     
       14. The method of  claim 12 , wherein the eluted molybdenum fraction is eluted from the solid phase extraction system before the eluted technetium fraction. 
     
     
       15. The method of  claim 11 , wherein separating at least a portion of the Tc-99m from the Mo-100 comprises:
 partitioning the irradiated liquid target matrix between an organic solvent phase and an aqueous phase to produce a product enriched in the Tc-99m. 
 
     
     
       16. The method of  claim 15 , wherein the organic solvent phase comprises methyl ethyl ketone. 
     
     
       17. The method of  claim 1 , wherein another portion of the Mo-100 in the fluid target matrix is transformed to Mo-99 in the irradiated fluid target matrix, and the method further comprising
 isolating Mo-100 and Mo-99 from the irradiated fluid target matrix to provide a recovered sample of molybdenum that is substantially free of a direct irradiation produced Tc-99m; and 
 separating at least a portion of Tc-99m derived from a natural decay of Mo-99 from the recovered sample of molybdenum. 
 
     
     
       18. The method of  claim 1 , further comprising producing a plurality of radionuclides:
 by concurrently producing at least one of F-18, N-13, O-15, or C-11, 
 wherein the fluid target matrix further comprises at least one of O-18, O-16, or N-14, wherein irradiating the fluid target matrix with the proton beam transforms at least a portion of Mo-100 to Tc-99m, and transforms at least a portion of the O-18 to F-18, at least a portion of the O-16 to N-13, at least a portion of the O-16 to O-15, or at least a portion of the N-14 to C-11, and thereby provide an the irradiated fluid target matrix; and 
 separating from the irradiated fluid target matrix at least a portion of the Tc-99m and at least a portion of the F-18, the N-13, O-15, and/or the C-11. 
 
     
     
       19. The method of  claim 18 , wherein the Mo-100 is derived from a water soluble molybdenum compound selected from the group consisting of molybdenum oxide, ammonium molybdate, and alkali metal molybdates. 
     
     
       20. The method of  claim 18 , wherein the O-18 is derived from H 2   18 O,  18 O 2 , or  100 Mo 18 O 3 , the O-16 is derived from H 2   16 O,  16 O 2 , or  100 Mo 16 O 3 , or the N-14 is derived from  14 NH 3 ,  14 NH 4   +1 ,  14 N 2 ,  14 N 16 O 3   −1 ,  14 N 18 O 3   −1 , or ( 14 NH 4 ) 6 Mo 7 O 24 . 
     
     
       21. The method of  claim 1 , further comprising:
 transferring an aqueous solution of a water soluble molybdenum compound comprising Mo-100 into a target assembly, 
 wherein the aqueous solution has a pH in a range from about 2 to about 12; wherein the target assembly comprises a target body and a beam window; wherein the target body comprises stainless steel, tantalum, a cobalt alloy, or a polyether ether ketone; and wherein the beam window comprises cobalt, titanium, tantalum, tungsten, stainless steel, gold, or alloys thereof. 
 
     
     
       22. The method of  claim 21 , wherein the beam window has a thickness in a range from approximately 0.3 μm to 50 μm. 
     
     
       23. The method of  claim 21 , wherein irradiating the fluid target matrix comprising Mo-100 with the proton beam is performed with proton energies in a range from about 7 MeV to about 30 MeV at a beam power within a range from approximately 1.5 kW to 15.0 kW.